When they spoke of poaching, they meant that they were hunting in the woods that belonged to the nobles. According to the traditions in the world, the feudal lord noble possessed the ownership of the entire manor, including the land and the things that grew on the land.
As for man-made items, or other things, like crops, that required manpower during growth, the labor would be able to shared, with parts of the profit being given back to the workers. However, the majority of all profits still belonged to the feudal lord.
In the woods, regardless of whether it be a plant or animal, since these things were not man-made, nor was anyone contributing manpower to their growth, they belonged to the feudal lord entirely. Thus, no one could attempt to invade such areas.
